Date	Event	Description
12 January 2012	New citation required but conclusions have not changed	New authors, other revisions as described above.
6 October 2011	New search has been performed	A new search strategy was developed. We used revised methods of the Cochrane Effective Practice and Organisation of Care (EPOC) Group to assess the risk of bias of included studies. We expanded the search to include Latin and Ibero‐American databases.